A New Class of Metallacarboranes:  Synthesis and Molecular Structure of the First Example of an Organolanthanide Compound Bearing an η 7-Carboranyl Ligand

The first organolanthanide compound containing an η 7-carboranyl ligand, [{[η 5:η 7-Me2C(C5H4)(C2B10H11)]Er}2{Na4(THF)9}] n (3), has been achieved by treatment of [η5-Me2C(C5H4)(C2B10H11)]ErCl2(THF)3 (1) or [η 5:η 6-Me2C(C5H4)(C2B10H11)]Er(THF)2 (2) with excess Na metal in THF. The Na+ ions in 3 can be replaced by Er3+ ions, giving the novel tetranuclear cluster [{η 5:η 7-Me2C(C5H4)(C2B10H11)}Er2(μ-Cl)(THF)3]2 (4).